An artist’s concept of a future biomanufacturing lab on Mars, powered by photovoltaic (solar power) technology. It will also synthesize food and medicines, and manufacture other needed materials, while recycling waste. (Credit: Davian Ho.)Sometime in the next couple of decades, humans will head to Mars for long-term missions of more than 400 days. Such lengthy stays mean building Martian cities, complete with safe habitats, labs, and other infrastructure. Future Martians will have to do a lot to survive. They’ll build their cities, make their own food, distill water, create fuel, manufacture medicines, and create other supplies. To do that, they’ll use manufacturing facilities that they bring along. That all requires power. Lots of it. As we all know, Mars is noticeably lacking in obvious ways to make electricity. So, what will our intrepid explorers do to generate power for their new lives on the Red Planet?
This flow chart shows the process humans on Mars will use as they synthesize the materials they need from the raw materials on the planet. The equipment they use will be transported from Earth (at first), but will need reliable power. (Credit: Aaron Berliner and Davian Ho, UC Berkeley)
Mars Needs Power!
Conventional wisdom says that nuclear power units similar to what powers other spacecraft are the best choice. They’re clean, reliable, and long-lasting. The downside is that they weigh a lot. A Mars-bound spacecraft will be very limited in what it can carry. Of course, it’ll have crew and fuel. However, all those people will need supplies, including power units to use on the surface. It turns out that most of the current rockets can only carry about 100 tons (not including fuel). Just one nuclear power plant supplying about a kilowatt of power would be about 9.5 tons. That’s not insurmountable, however. But, mission planners want to minimize a mission’s weight in order to get the most bang for the buck. So, what if there was a lighter alternative to nuclear? Like solar power?
That’s the question a pair of graduate students at the University of California at Berkeley wanted to answer. So, they did a research project looking at future power sources for Martian colonists. Aaron Berliner specializes in nuclear engineering while Anthony Abel is interested in advances in photovoltaic cells for solar power. Together, they analyzed the power needs for a six-person mission staying on Mars for 480 days. In particular, they looked at sites on Mars where solar power might make a lot of sense. And, what they found seems to confound the conventional wisdom.
Future Mars explorers who settle in the mid-latitudes of the planet (shown in yellow) could use photovoltaics for power. Note the locations of other missions previously sent to Mars. Many are also in the same regions and have used solar power for some aspects of their explorations. Credit: Anthony Abel and Aaron Berliner, UC Berkeley)
If our future Martians settle in the mid-latitudes, particularly around the planet’s equatorial regions, solar power stations could trump nuclear. Why is this? First of all, the mid-latitudes get a lot of sunlight, so why not take advantage of that? Second, solar power cells weigh less than nuclear power plants. To get the same power as a nuclear plant, new-generation solar tech would only take up about 8.3 tons of cargo. That’s a significant weight saving over nuclear.
What kind of power cells are we talking about here? Berliner and Abel looked at systems that use photovoltaic power with electrolysis. That is, they use electricity to split water into hydrogen and oxygen. The students also calculated that some of the energy generated during the daytime would be used to produce hydrogen gas for use in fuel cells. This is roughly similar to the way some homes and businesses here on Earth use solar power to store energy in Powerwalls and batteries for night-time use.
The cool news? All this solar power goodness is possible with current photovoltaic technologies. And, of course, the technology is always improving, so by the time a Mars mission is ready to lift off, whole new versions of today’s solar cells will be ready to use.
“The silicon panels that you have on your roof, with steel construction, glass backing, and so on, just won’t compete with the new and improved nuclear,” said Abel in a press release from UC Berkeley, “But these newer lightweight, flexible panels all of a sudden really, really change that conversation.”
Advantage: Solar Power
The advantages of solar on Mars outweigh the problems. Even though colonists might have to clear the dust off the cells every so often, their lighter weight means that more panels could be sent to Mars. That includes backups for the main systems. As newer, lighter cells come online, solar power could be the main source of power for future Martian colonies. That’s not to say nuclear power won’t be there, too. In the long run, colonists may need every power-generation technology they can get, both for reliability as well as flexibility. And, in the near future, with the need to keep costs down, solar power may well be the way to go.
For more information, the paper that Abel and Berliner wrote is titled “Photovoltaics-Driver Power Production Can Support Human Exploration on Mars”, and published in Frontiers in Astronomy and Space Sciences. Their work was funded by NASA as well as the National Science Foundation.
